Play is endemic in the animal kingdom and nowhere is play more prevalent than in the human species. Mammals in general and people in particular are born to play. Mammalian brains are not only hardwired to engage in and experience the positive feedback of play, the instinctual drive for play is deeply seated subcortically. Consequently, it is a very basic instinct and trait.
The subject of play has received considerable scientific and scholarly attention, particularly since the 1960's. That body of work is summarized below and citations to some of the principal sources are included. Those skilled in the art will appreciate that this is an ongoing study which adds to the fund of knowledge supporting the principles set forth herein.
Like most basic instincts, failure to actualize the trait has harmful consequences for the host system. Play deprivation has been thoroughly studied in several animal models while it has been observed in humans. At best, when occurring after major brain (neuronal) development, play deprivation leads directly to depression. At worst, whether experienced during ongoing brain development in juveniles or thereafter, play deprivation of any significant mode or duration contributes to antisocial and sometimes aggressive behavioral manifestations which can be violent.
On the other hand, allowing or fostering healthy play attitudes and adaptations have a positively beneficial impact on physical and emotional development. These benefits can be observed literally post-partum, when infant and mother engage in the most fundamental form of play, attunement, which serves to form the beneficial linkage between them. As the infant matures, s/he naturally experiences a range of play environments discussed more thoroughly below. These include, for example, rough and tumble play, social play, object play, competitive play, and many others. Each type or pattern of play aids in the enrichment of neuronal development and in turn manifests itself in emotional traits and what is now termed emotional intelligence. Play types are mutually reinforcing as developmental catalysts. So, as humans, healthy and active play aids the pathway development for such traits as teamwork, problem-solving, self-regulation, empathy and creativity, to mention but a few.
Play scientists experiment with animal models that translate to humans but, for obvious reasons, observe human play personalities. There is close correlation between the two—experimentation and observation. It has been determined that there is a continuum between what animal field research reveals and the presence of animal play personalities that demonstrates linkages to the fundamental development of human play personalities. Thus, Panksepp et al. demonstrated that play circuits reside in the survival center of the brain by studying the play patterns of decorticated rats. Effects of Neonatal Decortication on the Social Play of Juvenile Rats, Physiology and Behavior, 56 (1994) at 429-443. The decorticated rats nevertheless remained attuned to and engaged freely in complex rough and tumble play and vocal play signaling. Panksepp has demonstrated over the years the direct correlation between his rat models and human brain physiology.
Pellis et al. solidified Panksepp's work through extensive experimentation on rat and other mammalian models, showing solid evidence of the consequences of play deprivation. The Playful Brain, Venturing to the Limits of Neuroscience. Oneworld Books (2009). This work compiles animal play data substantiating the effects of play as a contributor to development both of organic cortical (neuronal) density and the socio-emotional behaviors attributable thereto. Likewise, Pellis et al. link play deprivation and suppression to diminished social, emotional and cognitive competency in a broad range of laboratory-controlled, play-observed social animals including rats and others.
Play is so deeply rooted in mammalian brain systems that it has been shown to be a fundamental drive, as are the drives for food, sleep and sex. As written by the present inventor in his book, Play: How it Shapes the Brain, Opens the Imagination and Invigorates the Soul, Avery (2009), the impulse to play is internally generated and generally pre-cognitive. Consequently, just as sleep deprivation is known to lead to the kind of cortical imbalance contributing to impaired judgment, play deprivation has a similar effect. The differences arise in the periodicity of the impairment, whereas sleep deprivation can manifest itself in a matter of days play deprivation requires longer periods of time before serious effects can be recorded. Nevertheless, suppression of this strong drive for play and playful activities seated in the survival centers of the brain inevitably and eventually suppresses healthy social development and interaction and can seriously impair judgment and emotional balance.
These roots of play spring from two fundamental factors that underlie all mammalian play. They are “attunement” and “temperament.”
Attunement arises at birth. In a healthy human mother-infant relationship, the two lock eyes and the infant exhibits an intrinsic response to the mother's gaze. It is a state that is hardwired into the nascent brain just as breathing and sleeping. It is an observable state, as one watches the facial expressions and posture of the infant. This is confirmed by Electroencephalography (EEG) studies which track the brain activity of both mother and infant. See Shore, Allan Affect Regulation and the Origin of Self: The Neurobiology of Emotional Development (1994), Lawrence Erlbaum & Associates (Pub.) Attunement is accompanied by a joyful state of play that prepares the infant to experience the entire range of play types discussed below.
Temperament develops in a human as the combination of nature and nurture. On the side of nature, a person's temperament is shaped by genetics and gating events such as the ability to perceive (cognitive threshold) and the person's state of developmental maturation. Nurture contributes to the person's temperament through the environment in which she develops from infancy through the juvenile years when much of her temperament becomes fixed. Exogenous environmental factors include exposure to a range of activities such as music and physical exercises, coupled with the dynamics of the family in which she is raised. Endogenous environmental factors impacting temperament include such matters as safety and nutrition.
One's temperament exhibits tendencies that evolve during childhood. One may show the tendencies toward shyness while others may find it more comfortable as an introverted or extroverted person. These, though, are tendencies and are not firmly fixed in the sense that one is predestined to a particular temperament. The Long Shadow of Temperament, Kagan, J. C. & Soudman, C. (2004), Harvard Univ. Press.
Attunement and temperament may be catalyzed positively and negatively. A child raised in a loving family with wholesome attention, having proper nutrition and living in a safe environment will tend to have positive attributes that display themselves in a rich and robust play personality. Contrariwise, there are factors that augur against the states of attunement and temperament that lead to that result. Anti-attunement and anti-temperament influences are most typically related to physical or mental disabilities. These include but are not limited to such factors as abuse, isolation, starvation and disease. However, except in the most extreme cases, these negative influences are capable of remediation and the person can then develop beneficial play patterns.
Within human play and its foundation of attunement and temperament emerges what is widely regarded as intrinsic motivation. Just as each play personality is uniquely individual, so too are an individual's intrinsic motivators. Intrinsic motivation is frequently defined as participating in an activity for its own sake, out of interest and for the pleasure and satisfaction from simply performing it. Intrinsic motivation does not necessitate an outside stimulus to foster its emergence. Educational research has shown that students with a more intrinsic motivational orientation will tend to outperform those who have been accustomed to extrinsic reward systems (C. Dweck, W. Glasser, A. Kohn). Education is not alone in these findings. Research in other fields has indicated similar results as it relates to job performance, innovation, self-management and more. Long-term behavioral change occurs when intrinsic motivators are engaged.
While many psychologists and social scientists have explored self-determination theories that include the roles of intrinsic and extrinsic motivation, they neglect to link the identification and development of intrinsic motivators with the survival drive to play. Perhaps this is because play was commonly denigrated as a “waste of time” and “unproductive” during the height of industrialized mass production, when focused attention on work was revered and nose-to-the-grindstone drive was considered what it took to get ahead. Or maybe it is because it has only been relatively recently that neuroscience has demonstrated play as a fundamental survival drive. In any case, there is no question that there has been an historic bias against play on many levels.
However, the world is changing rapidly and the traditional industrial-financial economy and its jobs are in major disruption. What is emerging is the global creative economy. The majority of the jobs of the future have not been invented yet.
Play is the genesis of innovation and fosters self-regulation, resiliency and creativity humans need to adapt to a rapidly changing world. Those who play have a competitive advantage.
Stanford Psychologist Albert Bandura's social learning theory, which emphasizes self-efficacy, highlights that external, environmental reinforcement as not the only factor to influence learning and behavior. He described intrinsic reinforcement as a form of internal reward, such as pride, satisfaction, and a sense of accomplishment. These contribute to the individual's belief in his own competencies and capacities, his self-efficacy. It is Bandura's research that has influenced David Kelley, Founder of IDEO, one of the world's most innovative design companies, and Founder of Stanford University's famed d.school, the Hasso Plattner Institute of Design. Bandura provided inspiration to David Kelley and his brother Tom's book, Creative Confidence: Unleashing the Creative Potential Within Us All. The Kelley brothers shatter the myth that only some people are creative. They show, and Play Science elaborates, that everyone is intrinsically creative.
Dan Pink, author of Drive: The Surprising Truth about What Motivates Us, shows that carrot and stick extrinsic motivators can achieve precisely the opposite of their intended aims. Rewards can transform an interesting task into a drudge. They can turn play into work. Traditional “if-then” rewards can give us less of what we want. They can:                Extinguish intrinsic motivation        Diminish performance        Crush creativity        Crowd out good behavior        Encourage cheating, shortcuts and unethical behavior        Become addictive, and        Foster short-term thinking.        
Nobody knows exactly how the emerging creative economy will fill the void left by industrialization. However, trends such as the DIY and Maker Movement indicate that the people who tap into and sustain their innate interests and talents will develop levels of mastery in skills very valuable for the future, all the while enjoying the beneficial outcomes of their biological design to play. This is in alignment with GoogleX leader Astro Teller recently indicating “we've just failed so far to get technology to its higher purpose, which is to get technology out of the way.” (techcrunch.com/2014/05/06/googlex-head-of-moonshots-astro-teller-technology-should-make-you-feel-more-human-not-less-human/)
The following, including the references cited therein, are representative of publications relating to the topic of play.
In his 1938 book, Homo Ludens or “Man the Player” (alternatively, “Playing Man”) (1950), Roy Publishers English Translation, Dutch historian, cultural theorist and professor, Johan Huizinga discusses the importance of the play element of culture and society. Huizinga uses the term “Play Theory” to define the conceptual space in which play occurs. Huizinga suggests that play is primary to and a necessary (though not sufficient) condition of the generation of culture.
Play-Its Role in Development and Evolution, edited by Jerome Bruner, Aslison Jolly, Kathy Sylva, (1976) Basic Books, is a seminal collection of essays and articles, edited to present the then-existing knowledge base about play.
Ontogeny and Phylogeny, (1977) The Belknap Press of Harvard University, by paleobiologist Stephen Jay Gould, painstakingly develops the evidence for neoteny as a basic biological pattern of design for humans and that play is a hallmark of neotenous creatures. This forms a credible basis for later anthropologic reviews that demonstrate human's hunter-gatherer heritage as being consistently playful.
Robert Fagen, Animal Play Behavior (1981) New York, Oxford University Press, presents a comprehensive, descriptive magnum opus on animal play that demonstrates the patterns of play, including body, object, social, gaming play, etc., as summarized hereinbelow.
Mihai Spariosu, Dionysius Reborn: Play and the Aesthetic Dimension in Modern Philosphical and Scientific Discourse, (1989) Cornell University Press, places into a broad perspective the historic and contemporary philosophical discourses relevant to play and contemporary science (though not neuroscience) including quantum theory. This work anticipates the later Panksepp and Pellis neuroscience findings that play is both rational and pre-rational.
In his work, Bright Air Brilliant Fire: On the Matter of the Mind, (1992) Basic Books, dual Nobelist Gerald Edelman provides a solid hypothesis and preliminary evidence for what now is becoming widely accepted as epigenetic cerebral cortical “turn-ons” prompted by environment (play) inputs which induce the creation of new cortical “maps.” As attempts to correlate clinical human play observations with basic science findings, a more comprehensive view of both the overall clinical expressions peculiar to play, and mammalian evolutionary heritage is becoming clearer with evidence from both camps to substantiate it.
Animal Play, Evolutionary, Comparative, and Ecological Perspectives, Marc Bekoff and John Byers (ed.) (1998) exemplifies the validity and utility of animal neuroscience as a base for the study of mammalian play patterns. The present inventor is the author of the article titled, Play as an Organizing Principle, Clinical Evidence and Personal Observations (Chap. 12). This contribution is a foundation for the synthesis between animal play patterns and deprivational findings in both animals and humans.
The Ambiguity of Play, Brian Sutton-Smith (1997) Harvard University Press is a foundational work describing play in all its variations and providing the ground for human flexibility adaptability and innovation.
Affective Neuroscience-The Foundations of Human and Animal Emotions, Jaak Panksepp (1998) Oxford University Press, is considered by many scientists a paradigm shifting work in the field of play neuroscience. Among other groundbreaking contributions to the science of play, this work by Panksepp, primarily studying and objectifying rat play and other basic rat behaviors, established play as a survival drive among playful social mammals.
The Nature of Play: Great Apes and Humans, Anthony Pelligrini, Peter K. Smith (2005) Guilford Press, studies both playground and ape ethologic observations and shows, for example, the importance of rough and tumble play in both humans and apes for subsequent social competency and development.
Sergio and Vivien Pellis, The Playful Brain, Venturing to the Limits of Neuroscience (2009) One World, Oxford, substantiates Panksepp's work, and extends it to demonstrate the behavioral consequences of adequate play, as well as the dire effects of deprivation.
The Archaeology of the Mind, Neuroevolutionary Origins of Human Emotions, Jaak Panksepp and Lucy Bivens (2012), W.W Norton & Co., New York, London, is another compendium of information concerning play in mammalian species. In their work, these authors demonstrate that the generation of play develops the cortical circuits necessary for social-emotional-cognitive competencies.
Those skilled in the art may also confer The American Journal of Play, on whose editorial board the present inventor serves, for additional scientific and scholarly works in the field.
As is apparent from the preceding summary, there is a robust literature on the science and application of play as a fundamental aspect of human development and healthy human emotions. However, there are no means for translating that fund of essential knowledge into practical applications that can benefit individuals either in their personal or business lives. By demonstrating, interpreting and monitoring the biomarkers that identify play, its benefits and the consequences of its deprivation, the play-related data can be translated into action policies and cross-sector applications.